Representing a new productive force, Brain-Computer Interface (BCI) stands at the forefront of merging life sciences and information technology. It's a pivotal direction for the future of industrial development.
Lately, there have been significant advancements in BCI clinical trials both domestically and internationally. Last week, Neuralink, founded by Elon Musk, showcased a video of the first BCI patient playing chess and video games through thought alone. A month or two ago, a team led by Professor Hong Bo from Tsinghua University Medical School announced their collaboration with Capital Medical University Xuanwu Hospital and Beijing Tiantan Hospital. They've successfully aided quadriplegic patients in drinking water autonomously and controlling computer cursors with brain activity using a semi-invasive BCI.
Does this indicate that BCIs, as a novel therapeutic method, will become widely accessible soon? How far is this cutting-edge technology from making "science fiction a reality"? Our reporters have exclusively interviewed Professor Hong Bo to explore these questions.
The Zhao Guoguang team at Xuanwu Hospital, Capital Medical University, is currently performing NEO implantation surgery.
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Wireless Minimally Invasive Brain-Machine Interface System NEO and Its Intrabody Design and Synthesis Diagram.
■Reporter: Xu Qimin
Following the announcement at the end of January that the wireless minimally invasive brain-machine interface (NEO) enabled a patient, who had been unable to care for themselves for 15 years due to spinal cord injury, to independently control drinking water with their mind, Professor Hong Bo from the Biomedical Engineering School of Tsinghua University Medical School has been leading his team in developing the next phase of rehabilitation and training plans for the patient.
In October 2023, Professor Hong's team, in collaboration with Xuanwu Hospital of Capital Medical University, implanted their independently developed semi-invasive wireless minimally invasive brain-machine interface into the first test patient. After over three months of rehabilitation training, Mr. Yang, who had been paralyzed for 15 years, was able to drink water independently using his mind control, and his arms became stronger. Holding his one-year-old granddaughter on his knees, Mr. Yang could embrace her with his arms.
In December last year, Hong's team also collaborated with Beijing Tiantan Hospital affiliated with Capital Medical University to successfully implant the NEO into the skull of another patient, Xiao Bai, who suffers from high-level paraplegia. Last month, this patient managed to control the movement of a computer cursor using brain activity.
"The surprising effects have increased patients' expectations towards brain-machine interfaces. Now, our biggest pressure and challenge is how to bring more medical benefits to the patients in the future," said Hong, who has been engaged in neural engineering research for over 30 years and devoted to brain-machine interfaces for more than 20 years. He has a clear and profound understanding of this field. According to him, despite the global popularity of brain-machine interfaces, there are still many scientific and industrial challenges ahead. "No single technology is a panacea or a one-time solution. Brain-machine interfaces have built an information bridge between the human brain and computers, but this is just the first step."
Focusing on 'Clinical Application'
Pioneering a 'Semi-invasive' Innovation
Domestically, clinical trials for intracranial implantation began earlier than Neuralink, thanks to the initial development goal of "clinical application." Semi-invasive brain-machine interfaces have carved out a niche for themselves in the field with their unique advantages.
"I'm deeply grateful to the two patients who have received NEO implants, for they chose to trust us without prior examples to follow," Professor Hong expressed. For this trust, the team is committed to making every effort.
There's a global consensus in the brain-machine interface field that "clinical application is definitely the future trend of development." Since announcing his venture into the brain-machine interface field in 2017, Elon Musk has aimed to use brain-machine interfaces in human patients.
"For invasive brain-machine interfaces to be used in human patients, approval from national health regulatory authorities is required, which sets a very high threshold," said Hong. Even top enterprises like Neuralink spent years obtaining clinical approval from the FDA. Therefore, he has been pondering and exploring possible shortcuts to achieve clearer signal acquisition and transmission while quickly meeting clinical application standards.
In 2004, Hong, who was then working on non-invasive brain electricity research, went to Johns Hopkins University School of Medicine as a visiting scholar, where he was exposed to intracranial brain electricity recording and implantable brain-machine interfaces. After returning to China in 2005, through extensive discussions with numerous clinical doctors, he gradually conceived the idea of developing a semi-invasive brain-machine interface. In 2013, he published his first paper on semi-invasive brain-machine interfaces. At that time, Musk had not yet entered the brain-machine interface field, and there were only invasive and non-invasive types of brain-machine interfaces in the world.
If we imagine the human brain as an egg, the skull is like the eggshell, the dura mater underneath the skull is similar to the eggshell membrane, and the brain tissue is like the egg white and yolk. "Detecting brain electrical signals from outside the skull is the safest but yields the lowest quality of signals; inserting electrodes into the brain tissue provides the best signals but inevitably brings the risk of damage." Hong finally came up with the idea of placing electrodes inside the skull but outside the dura mater—this is akin to listening to a conversation inside a room by pressing an ear against the wall, which is certainly better than listening from outside the building and also avoids disturbing those inside.
In developing the electrodes for the semi-invasive brain-machine interface, Hong's team focused on clinical application and future commercialization, employing minimally invasive implantation, wireless charging, and wireless signal transmission technologies. The team only uses materials approved for long-term implantation in humans by the national regulatory authorities, such as platinum-iridium alloys, titanium, and silicone, to develop the implanted devices, thereby reducing the difficulty of "clinical application."
Because of this clear goal, NEO was able to smoothly obtain the medical device type inspection report and pass the hospital's ethical review, starting clinical trials earlier than Neuralink.
Of course, even though a relative balance between signal quality and bodily harm has been achieved, the semi-invasive brain-machine interface is not a "cure-all." It has its specific range of applicability. Hong told the reporter that NEO is particularly good at transmitting and collecting signals from the superficial layers of the cerebral cortex but not as effective in dealing with signals from deeper layers of the cortex as implantable brain-machine interfaces. "However, within a certain range, we can leverage signal processing and machine learning technologies to maximize the clinical potential of these signals, thereby benefiting patients."
Exploring Clinical Applications
Requires Pioneering Efforts in Brain Science
When new treatment methods ignite hope in patients previously deemed incurable, they often have more demands. However, for brain-machine interfaces just starting in clinical settings, developing effective treatment plans still relies on breakthroughs in foundational brain science research.
In selecting clinical trial participants, Hong's team first considered patients with high-level paralysis caused by spinal cord injuries.
China has millions of patients with high-level paraplegia due to spinal cord injuries. The first patient to receive a NEO implant, Mr. Yang, became paralyzed for 15 years due to a car accident and was unable to take care of himself. Before the implantation of the brain-machine interface, the team was concerned about potential infections and whether the electrodes and internal mechanisms would function properly. Now, all these concerns have been successfully addressed.
Behind Old Yang's scalp, there's only a slightly raised area indicating the presence of NEO implant. Every day, he comes to the makeshift studio set up in his home, activates the brain-machine interface using a wireless controller, then puts on pneumatic gloves to start a two-hour rehabilitation session.
Hong Bo explained that the NEO implanted beneath the skull can interpret commands from Old Yang's brain cortex. For example, when he thinks of "grasping a cup," NEO transmits the corresponding brain signals to the computer, which then drives the pneumatic gloves to move Old Yang's hands accordingly to fulfill the command.
After over three months of training, Old Yang's hands have regained strength, and he has gradually regained sensation of hot and cold. This was previously unimaginable for him, as he used to feel only pain regardless of temperature.
Hong Bo elaborated that while these brain signals are being interpreted by NEO, they also transmit down to the site of spinal cord injury. Simultaneously, when the pneumatic gloves move the limbs in response to corresponding actions, the relevant electrical signals feedback to the site of spinal cord injury. "Through repeated stimulation of neural electrical signals, the damaged or disconnected neural circuits may slowly rebuild."
As the participants' hand movements gradually recovered, the pressure on the research team increased. "When patients see hope, they expect further improvement, but as a new clinical trial, we must balance the risks of the trial with the health benefits for the patients." Hong Bo revealed that the team has been studying and discussing Old Yang's next steps in rehabilitation and training programs.
For patients, seeing their fingers become more agile and their arms gradually regain strength sparks hopes of "standing up." Hong Bo admitted that from the current known global scientific research results, this goal is still unreachable.
Although brain-machine interfaces seem miraculous, they are still just intermediate devices for communicating between the human body and computers. Whether such devices can be used for therapeutic purposes depends on people's deep understanding of neuroscience. For example, training hand movements through EEG devices is possible because scientists have a fairly clear understanding of the corresponding neural circuits. "However, the neural circuits and networks involved in standing and walking are much more complex than grasping and gripping," said Hong Bo, noting that it's challenging for most patients to grasp these deep-seated factors, leading to psychological disparities when expectations cannot be met.
In December 2023, Xiao Bai, 36, underwent NEO implant surgery at Beijing Temple of Heaven Hospital. Having been paralyzed from the neck down for five years, he is the second NEO trial participant, currently practicing moving the cursor on a computer screen through thoughts: thinking "clench fist" moves the cursor downwards; thinking "lift elbow" moves the cursor upwards. Through continuous practice, Xiao Bai gradually mastered the technique of controlling the cursor with his mind.
"Although they are both high-level paraplegics, the extent of nerve damage varies among each patient, resulting in significant differences in the rehabilitation effects after implanting the brain-machine interface," Hong Bo disclosed. The research team plans to complete 3 to 5 NEO implants first to determine the hardware parameters and software algorithms required for large-scale clinical trials. They will establish scientifically reasonable inclusion criteria and clinical endpoints, then conduct large-scale clinical trials following the specifications of the regulatory authorities, aiming to obtain statistically significant therapeutic effects and lay the foundation for NEO to apply for Class III medical device licenses. "If everything goes smoothly, this will be the world's first approved implanted medical device in this field."
The rise of a new generation of human-machine interfaces bridges the gap between the human brain and AI, paving the way for brain-machine interfaces to move from clinical settings to ordinary people's lives in the future. Perhaps in another 20 years, as a new generation of human-machine interfaces, everyone could have a brain-machine interface.
The emergence of brain-machine interfaces seems to have transported people into a futuristic world overnight, where telepathy, superpowers, and even digital immortality depicted in science fiction movies seem within reach.
The brain-machine interface serves as a bridge between the human brain and artificial intelligence (AI). As the new bridge for the next generation of human-machine interfaces, "perhaps in another 20 years, everyone could have a brain-machine interface, and implanting it would be as simple as undergoing a minor cosmetic surgery," Hong Bo predicted. He believes that brain-machine interfaces will change the future form of human society just like mobile phones.
However, he also cautioned that there is still a considerable gap between science fiction and reality. While the imagination space for brain-machine interfaces is vast, achieving them step by step requires substantial investment in research, clinical trials, and industry.
After the safety of engineering and surgery has been proven, how to make good use of brain-machine interfaces remains an open question. Musk once mentioned that Neuralink's next goal is to develop a brain-machine interface called Blindsight, which is expected to restore visual function. Even if the patient loses both eyes and optic nerves, Neuralink can help them regain sight.
Hong Bo admitted that he was surprised when he heard about Musk's involvement in the field of brain-machine interfaces in 2016. He believed that the power of capital is formidable, and the ability to mobilize resources far exceeds that of a research team alone. He thinks Musk's engineering and commercial capabilities are very strong, and the technology and design used in the "telepathy" product developed by Neuralink, as well as the surgical robots, demonstrate extremely strong engineering capabilities, "done very beautifully."
However, after years of effort, Hong Bo feels that the field of brain-machine interfaces is a vast territory, "as long as you focus on a direction and do your best, you can also establish China's unique position in this field."
Although Hong Bo has been staying in the laboratory, two entrepreneurial teams have emerged from his students: one is engaged in EEG-related algorithm research in Beijing, and the other focuses on industrializing cutting-edge devices for brain-machine interfaces in Zhangjiang, Shanghai. The NEO implanted in the patient's skull this time came from this Shanghai-based company. "The close collaboration between academia and industry is particularly crucial in the field of brain-computer interfaces," says Hong Bo. "For brain-computer interfaces to be used clinically on humans, there are stringent requirements for the entire production system. For instance, production must take place in GMP cleanrooms, strict quality control measures must be implemented, and extensive standardized testing must be conducted to meet the dozens of requirements set by the national regulatory authorities for implantable devices. These tasks can only be accomplished by corporate entities.
"When Mr. Yang's clinical case made headlines, we saw a surge of patients coming in every day," says Hong Bo. "Only by targeting three categories of medical device standards right from the R&D stage and simultaneously driving clinical exploration and engineering development can we, after devising clinical treatment protocols, swiftly meet the needs of more patients."
